That question is intrinsic to the art of outdoor cooking. Like most good questions, it is not just a simple answer, although there are some simple aspects involved. That is what we want to explore here. Topics explaining how you can create and maintain heat with charcoal to meet your desired temperature on a charcoal grill.
Whether you are experienced firing a mound of coals, or a new player in this arena of cooking, we will give you details about cooking styles and how to accomplish them with charcoal fuel. When you finish this article you will understand how charcoal grilling works, how to control it, and some different ways to utilize this simple fuel.
Basics of Heat & Charcoal
Charcoal is pretty amazing stuff that dates back millennia. Wood is transformed into charcoal through pyrolysis, a contained ‘burn’ with little to no oxygen. What’s left will burn very hot and typically very clean when re-ignited.
In a controlled environment with air blown into the mix, charcoal runs as high as a couple thousand degrees Fahrenheit. In an open grill the burn temp is about 1000, radiant heat is running about 700. Distance diminishes the temperature very rapidly.
So your goal in cooking with charcoal is to find the right mix of volume of burning coals, distance from the food to be cooked and duration of time for the cooking process. You can basically think of distance as two broad choices for cooking; direct or indirect heat.
Direct cooking, or grilling, you fire up the heat to a very high level and sear your food directly over the top.
Indirect usually has the heat to the side, or beneath a shield, with heat circulating naturally around the food via convection. That is very simply put, we will look at the nuances within the categories and approaches to get there.
Controlling Heat on a Charcoal Grill
For the sake of continuity we’re going to use a kettle style grill as the basis for approaching charcoal cooking. It is a very versatile unit that allows for many types of cooking. This is not unique to kettles, there are many great products in the market that will cook in different ways, however kettle styles are in use by many folks, and certainly known or used in the past by a large majority of you. As a result, it makes a relatable standard by which to contrast, compare and complete cooking goals.
How Much Charcoal Do I Need?
The best way to start your coals is with a chimney, also pretty ubiquitous amongst those who barbecue. Commonly these hold about 100 coals which gives us another collective basis that is consistent to consider. With room for a small wad of paper, they light quickly and get coals to that light coating of ash stage that means they are ready to use. Based on that standard, here is a chart with the percentage of the chimney filled up, and those coals evenly spread along the bottom of the kettle, and the resulting temperature roughly at the grill level.
| 25% CHIMNEY | 50% CHIMNEY | 75% CHIMNEY | 100% CHIMNEY | |
|---|---|---|---|---|
| Cooking fish or adding coal to light the smoker box | Low Heat 250° — 350° | |||
| Tailgate foods: burgers, hotdogs, brats, etc. | Medium Heat 350° — 450° | |||
| Ideal grilling temperature | Medium High 400° — 450° | |||
| Ideal temperature for searing steaks | High Heat 450° — 600° |
What we are not going to spend time on here is using wood. Kettles work well with wood chips and wood chunks. Any of the techniques we discuss here will allow for the integration of wood to help flavor your food. Other than occasional flame ups, wood will not affect the temperatures involved.
Hands-on Direct Heat Test
The basic rule of thumb is to spread the hot coals three inches out past the edges of the food to be grilled. If you are looking for a very high heat, searing a thinner steak for example or putting a crust on a slow cooked item, this is an important rule for focused heat. It also works with more delicate grilling, fish or thin chicken, by spreading out fewer coals with some gaps you get a good soft or medium heat flow.
| HIGH | MEDIUM-HIGH | MEDIUM | MEDIUM-LOW | LOW | |
|---|---|---|---|---|---|
| 2 — 3 seconds | 450° — 600° | ||||
| 4 — 5 seconds | 350° — 450° | ||||
| 6 — 7 seconds | 325° — 375° | ||||
| 8 — 10 seconds | 250° — 325° | ||||
| 10 – 15 seconds | 200° — 250° |
Alternatively, you can grab a infrared gun. They provide quick surface temperature readings and they’re a fun tool to have around.
Indirect (Low & Slow) cooking
One nice feature of the kettle cooker is that it contains heat pretty well, so you can spread a layer of coals across the bottom and use most of the grilling surface. However, if you have fewer items split the space by putting the coals all to one side and you can get the best of both worlds.
Directly over the coals will give you good searing temperatures, if the food is coming up too quickly or causing flare ups, move it to the cooler side. Very helpful if you are cooking steaks to differing levels of doneness for your guests or family.
This is really where the kettle cooker shines. You can use the split coal layout above, put all your food on the cool side, cover it and wait, getting great results. To simplify this process you could pick up the Slow-N-Sear by SnS Grills. This layout is also the basis for cooking with the reverse sear method for nice big steaks.
One of the most used methods is a parallel layout, coals banked against two opposite sides of the kettle, to cook indirectly.
This is the most versatile layout for cooking with a kettle. You can manage the vents, with your coals added as needed, to maintain slow smoking temperatures in the 250°F range. You can also go heavier with coals and boost that temperature up to 350°F, the range you want to cook a small turkey, bone in chicken pieces, or any kind of roasted meat. Adding 6 coals every hour will maintain the lower range, 10 will keep you at the higher range. A temperature reader designed for BBQ will help monitor internal and ambient temperature simultaneously.
Lowest and slowest cooking method
The snake method of burning charcoal offers the most controlled burn for using a kettle cooker, one that can be extended into hours of cooking. We admit, this is a fun style to impress your buddies, but it’s also effective. You lay about 100 pieces of the charcoal in a spiral pattern (around the inside outer edge of the grill) mixed in with wood chips or chunks if you choose. Then you add in a few hot coals to one end of the snake which will start the slow burning process.
This allows for an even smoke without the need to worry about wood chips catching on fire and burning up too quickly. It also lets you maintain that low temperature for the long periods of time needed for some dishes.
Controlling Temperature with Airflow
The last item, and a very crucial one to getting the results that you want, is controlling air flow. We know about heat getting started, and fuel from the charcoal and such. The last ingredient to the recipe for cooking with fire is getting right amount of oxygen to feed the flames.
The kettle style barbecue, and most other units, have vents at the bottom and in the domed lid cover. Controlling the vents helps regulate the heat and maintains the convection process of moving air. Wide open, the draft from these vents will burn through charcoal and keep the maximum heat going from the charcoal that you have used. Open grilling, without the lid, will do the same thing, allowing unlimited air to the coals.
Indirect and the snake method will need some control by you to help keep the fire alive without having it burn up too quickly. In general, you’ll want to keep the bottom vents open about halfway or more.
You tend to get better control using the top vents. With heat and smoke rising, you can also help contain the smoke to better flavor your food. Damping down the upper vents to a small crack will keep your fuel burn more controlled. Watch for too much white smoke, that’s a smoldering smoke that can have an acrid flavor, let the coals have a bit more air. Either use an ambient thermometer in the area with the meat, or use the hand method right over the vents. This will give you an idea of how the heat is flowing around your food.
Happy Smokin’!
It never fails: when I have friends over, hungry and ready to eat I can never maintain the correct temperature and everyone sits around and waits for me to pull off the food, add more coals and then wait to put the meat back once the coals have become fully lit..
I hope that these guidelines help, happy grillin!
C or F? You probably do not understand my comment or are completely oblivious of the world out there….
Wow. Let’s play nice in the sandbox. Farenheit. 225 degrees F is around the ideal temperature for long, slow smoking of meats on a grill or smoker. That would be around 107 degrees C.
You can usually easily tell the difference by the numbers…. C temps are always much lower numbers than you would cook anything at a Farenheit temp… About the only thing you could cook at 107 degrees F would be to maybe make jerky in a dehydrator for about 6-8 hours. 225 C would push the temp way up to about 437 F, which is generally way high even for oven-roasting meat…
I just started using a smoker last year. I started with an electric smoker, but found it wont give me that nice bark. I just started trying my weber. Its exciting but harder. I love feeding people and love food. I hope to have the skills to make it all come together someday. Thanks
Will this method work for using a rotisserie on your Weber. Looking to cook a bottom round roast, I’m guessing 2 hrs at around 275? Thoughts?
I haven’t played around with the rotisserie, but I’d try lighting a quarter-chimney of coals and pouring the lit coals on three-quarters of a chimney of unlit coals. You’ll need to close the vents most of the way to keep the temperature down to 275 degrees. If you can hold that temperature, you should get at least 2 hours out of this setup. I’d recommend a wireless probe thermometer like the Meater to monitor your pit temperature so you can dial in the airflow just right.